Screw nut



FIG. 1 is a perspective view of a screw nut;

FIG. 2 is a front view of a screw nut;

FIG. 3 is a rear view of a screw nut;

FIG. 4 is a left side view of a screw nut;

FIG. 5 is a right side view of a screw nut;

FIG. 6 is a top view of a screw nut; and,

FIG. 7 is a bottom view of a screw nut.

The broken line showing of the screw nut in FIG. 8 is for environmental purposes only and forms no part of the claimed design. 

CLAIM The ornamental design for a screw nut, as shown and described. 